Determinantes metabólicos, clínicos e psicossociais da perda de peso durante o processo da cirurgia bariátrica.

Abstract

INTRODUCTION: Obesity is characterized as a multifactorial chronic condition involving metabolic, clinical, and psychosocial alterations. Although bariatric surgery is recognized as the most effective treatment for sustained weight loss, the mechanisms determining its outcomes include a complex interaction among metabolic biomarkers, lifestyle factors, and mental health. Investigating these determinants in an integrated manner is essential to understand the weight loss process in the surgical context. OBJECTIVE: To investigate the metabolic, clinical, and psychosocial factors related to weight loss in the early postoperative period of bariatric surgery, approximately four months of follow-up, considering the interaction between gut microbiota, bile acids, follistatin, lifestyle, and mental health. MANUSCRIPT 1: Introduction: Obesity is a multifactorial chronic condition associated with high morbidity and mortality and increased risk of cardiovascular and metabolic diseases. Bariatric surgery, particularly Roux-en-Y gastric bypass and sleeve gastrectomy, is the most effective intervention for sustained weight loss and metabolic improvement. Objective: To review the literature on the relationship between weight loss after bariatric surgery, gut microbiota, bile acids, and follistatin. Methodology: A literature search was conducted in PubMed, Scopus, Web of Science, LILACS, and SciELO databases, covering publications between 2019 and 2025, in Portuguese, English, and Spanish. Studies involving humans and animal models that evaluated weight loss and at least one biomarker of interest were included. Results: Twenty four articles were included. Findings indicate that bariatric surgery promotes increased bacterial diversity, qualitative and quantitative changes in bile acid metabolism, and early elevation of follistatin levels. These factors are associated with weight loss and improved insulin sensitivity. Conclusion: The interaction among gut microbiota, bile acids, and follistatin levels constitutes a central metabolic axis that contributes to successful weight loss and metabolic benefits following bariatric surgery. Keywords: Bariatric surgery; Gut microbiota; Bile acids; Follistatin; Weight loss. MANUSCRIPT 2: Introduction: Bariatric surgery promotes significant weight loss and rapid metabolic improvement. However, the role of bile acids in this process during the early postoperative period remains incompletely understood. Objective: To evaluate early anthropometric and metabolic changes, including hepatic markers and bile acids, after bariatric surgery and their association with weight loss at four months. Methods: Cross sectional observational with assessments in the preoperative period and four months after bariatric surgery. Total serum bile acids, lipid profile, glycemia, liver enzymes, C-reactive protein, and uric acid were analyzed. Weight loss was expressed as percentage of total weight loss (%TWL) and percentage of excess weight loss (%EWL). Physical activity was assessed using the short version of the International Physical Activity Questionnaire (IPAQ). Results: The sample consisted of eight women. A significant reduction in body weight and BMI was observed after four months, with %TWL of 20.2 ± 3.8% and %EWL of 60.8 ± 13.1% (p < 0.001). There was a significant decrease in LDL-cholesterol (p = 0.015) and gamma glutamyltransferase (p = 0.021), while total bile acids did not show significant changes. A positive correlation was identified between %TWL and reduction in uric acid (ρ = 0.786; p = 0.028). No associations were observed between weight loss and physical activity practice. Conclusion: Bariatric surgery promoted expressive weight loss and early metabolic improvement, whereas changes in total bile acid levels were not observed in the early period, suggesting a progressive adaptation of this metabolic axis. MANUSCRIPT 3: Introduction: Obesity is a multifactorial chronic condition associated with important psychosocial repercussions. Although bariatric surgery is effective for sustained weight loss, its effects on body image perception and mental health in the early postoperative period remain poorly understood. Objective: To evaluate changes in body image perception and mental health indicators in patients undergoing bariatric surgery during the early postoperative period. Methodology: Cross-sectional observational study conducted with 10 adult individuals followed in a specialized service. Body image perception was assessed using the Multidimensional Body-Self Relations Questionnaire – Appearance Scales (MBSRQ-AS), and mental health was evaluated using the Perceived Stress Scale (PSS-10), Generalized Anxiety Disorder scale (GAD-7), and Patient Health Questionnaire (PHQ-9), applied in the preoperative period and approximately four months after surgery. Results: A reduction in body weight and body mass index was observed in the early postoperative period, along with improvements in specific domains of body image perception and reduction of dysfunctional eating behaviors. Conversely, mental health indicators did not show relevant changes during the evaluated period. Conclusion: In the early postoperative period of bariatric surgery, improvements in body image perception and eating behavior are more evident than changes in mental health indicators, suggesting that psychological adaptation occurs gradually and reinforcing the importance of continuous psychosocial follow-up.